Laser operating device for intracavitary surgery

ABSTRACT

This invention relates to an intracavitary laser operating device using a laser. 
     The device, has a catheter (2) accommodating laser light projecting fibers, a pulse laser oscillator device (1), an acoustic detector (4) detecting the acoustic wave generated from the diseased portion, an acoustic analyzer (5) analyzing the acoustic wave from the acoustic detector (4) and obtaining the amplitude change data and spectrum data of the acoustic wave, and a controller (7) for calculating the optimum condition of the projection of the laser light to be projected to the diseased part depending on the data from the acoustic analyzer (5) and controlling the pulse laser oscillator device (1) based on said optimum condition of the projection. 
     According the the device mentioned above, since the laser light can be projected to the diseased part based on the optimum condition of the projection, it is possible to avoid an occurrence of a risk that a normal blood vessel wall is damaged or carbonized or that a perforation in the blood vessel or new re-stenosis is formed.

FIELD OF THE INVENTION

The present invention relates to a laser operating device forintracavitary surgery, and more in particular to a laser operatingdevice for intracavitary surgery which is used for removing a diseasedpart inside a cavity using laser light.

BACKGROUND OF THE INVENTION

In the prior art, there have been contrived various kinds of devices formedical treatment diagnosis and methods thereof for removing, e.g. astenosis or occlusion of a blood vessel and an atheroma due to such asan arteriosclerosis or such as calculus in a kidney or urethra.

A bypass operation is the most assured treatment method in which alesion is completely removed by replacing a blood vessel which includesa diseased part with one of the patient's own blood vessels or with anartificial blood vessel, for example. However, since this method isfollowed by a surgery in which a vital organism is cut open, the vitalbody is subjected to a burden and a large amount of costs is needed forthe treatment. Moreover, although a drug treatment is also adopted, itis effective only for solution of a thrombus and it has been difficultto remove an atheroma focus.

Therefore, there has been recently adopted a treatment that a catheteris inserted into a tubular cavity from the outside of a body and reachesa diseased part so as to directly remove a cause of an obstacle.

One treatment is performed in a manner that a balloon catheter having aballoon attached on its distal tip portion is used and the balloonexpanded when it is reaches the diseased part so that the stenosis ofthe tubular cavity is mechanically expanded. However, since the stenosisis simply expanded, e.g. the diseased focus of the arteriosclerosis orthrombus which causes a stenosis can not be removed, a probability of arelapse of a disease in a short period is high. Moreover, in the casesthat the blood vessel is entirely occluded and that the arteriosclerosisis so advanced as to cause a calcification, it becomes difficult totreat with a blood vessel.

The other treatment is a method using laser light such as YAG laser orargon laser, wherein a metallic or ceramic chip attached to the tip ofthe catheter is heated by the laser light irradiated from the tip of anoptical fiber so that the heated chip is pressed onto the diseased partso as to burn out the diseased part. According to this method, thoughthe diseased part can be removed, the control of the light heating poweris difficult and if the chip is overheated, a normal vessel wall isdamaged or carbonized so that there may occur a new risk of vascularperforation or a new re-stenosis. Moreover, in case the vessel istortuous or completely occluded, it is not available because the chipcan not be inserted.

Therefore, it is also adopted that the laser light from such as YAGlaser, argon laser or excimer laser is projected to the diseased partfrom the tip of the fiber so as to vaporize the diseased part directly.Since the laser light directly vaporizes the projected portion, thelaser light is available also for a completely occluded diseased part.And since the output of the laser can be controlled, upon controllingthe amplitude, pulse width and pulse intervals of the pulse laser, it ispossible to control the power with high accuracy.

By the way, in the intracavitary laser operating device of a directirradiation type mentioned above, the operator controls the output ofthe laser light source or controls the amplitude, pulse width and pulseintervals in the case of a pulse laser according to the sort of thediseased part such as atheroma, thrombus and carbonization and to thedegree of the advance of the disease state, whereby the power control isperformed, but it has been impossible to control the power whileconfirming the state of the diseased part during the irradiation of thelaser.

With further detailed description, since there is a fear of damaging thecavity if a big power is abruptly projected to the diseased part byusing the catheter mentioned above, it is necessary to divide the powerof the laser light into several grades so as to be gradually raised up.In this case, it is necessary to confirm the changing condition of thediseased part by, e.g., endoscopic fibers every time the power is raisedup, so that it takes much time and labor.

The present invention has been made considering the problem mentionedabove and has its object to provide an intracavitary laser operatingdevice in which the power control can be performed confirming the stateof the diseased part during the irradiation of the laser.

DISCLOSURE OF THE INVENTION

In order to accomplish the object mentioned above, the intracavitarylaser operating device of the present invention is an operating devicefor projecting laser light to a diseased part through laser lightprojecting fibers by inserting a catheter accommodating the laser lightprojecting fibers into a cavity, comprising;

a pulse laser oscillator for generating laser light of a predeterminedcycle and applying to optical fibers, an acoustic wave receiver fordetecting an acoustic wave generated from a diseased portion in responseto the projection of the pulse laser, an acoustic analyzer for analyzingthe acoustic wave from the acoustic receiver and obtaining the amplitudechanging data and spectral data of the acoustic wave, and a controllerfor calculating the optimum condition of the projection of the laserlight to be projected to the diseased part based on the data from theacoustic analyzer and for controlling said pulse laser oscillatordepending on said optimum projection condition.

According to the present invention as described above, when the catheteraccommodating the laser light projecting fibers is inserted into thecavity so that the laser light is projected to the diseased part throughthe laser light projecting fibers, a sonic wave is generated from thediseased part because of the thermal expansion caused by a sudden heatabsorption at a neighborhood of a vaporization starting portion of thediseased part in accordance with the output projection of the pulselaser and the generation of the sonic wave can be detected by theacoustic wave detecting unit. The acoustic wave is analyzed by theacoustic analyzer so as to obtain the amplitude changing data and thespectral data of the acoustic wave. Subsequently, in the controller, theoptimum projection condition of the laser light (amplitude, pulse widthand pulse intervals) to be projected to the diseased part depending onthe data from the acoustic analyzer is calculated and the pulse laseroscillator is controlled depending on said optimum projection condition,whereby the laser light can be projected to the diseased part under theoptimum condition of the projection.

Accordingly there can be avoided a fear that, a normal blood vessel wallis damaged or carbonized resulting in occurrence of a risk of aperforation of a blood vessel or new re-stenosis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an embodiment of an intracavitarylaser operating device,

FIG. 2 is a sectional view of a catheter,

FIG. 3 is a block diagram showing, e.g., a pulse laser oscillator,controller and image device of the intracavitary laser operating device,

FIG. 4 is a schematic diagram showing an example of said intracavitarylaser operating device applied to a human body, and

FIG. 5 is a flow chart showing the operational process of theintracavitary laser operating device.

OPTIMUM EMBODIMENT OF THE INVENTION

An embodiment of the present invention is explained hereinafter withreference to the drawings.

As shown in FIG. 1, the intracavitary laser operating device of thepresent embodiment comprises a pulse laser oscillator (1), a catheter(2) for operation accommodating endoscopic fibers for endoscopy of adiseased part, illumination light guide, flush liquid passage hole,balloon dilation liquid passage hole, laser light projecting fibers andtip portion control wire, image device (3) for displaying a form of anendoscopic image and a fluorescent spectrum analysis and recording theimage data, acoustic detector (4) for receiving an acoustic wavegenerated from the diseased part in accordance with the laserprojection, acoustic analyzer (5) for analyzing the wave from theacoustic receiver and obtaining the amplitude changing data of theacoustic wave and the spectral data, and comprising a controller (7) forcontrolling the application of the light to said catheter (2) through aninterface (6) and controlling the charge of the liquid and forcalculating the optimum projection condition (amplitude, pulse width andpulse interval) of the laser light to be projected to the diseased partdepending on the data from the acoustic analyzer (5) and controllingsaid pulse laser oscillator based on said optimum projection condition.Moreover, (8) denotes a balloon for stopping a blood flow to be fixed,which is attached to the distal portion of the catheter (2).

The above mentioned acoustic detector (4) comprising a microphonedetects an acoustic wave generated from the diseased part because of thethermal expansion caused by the sudden thermal absorption at theneighborhood of the vaporization starting portion by receiving the laserprojection onto the diseased tissue.

The above mentioned acoustic analyzer (5) removes a noise such as aheart beat from the acoustic waves detected by the acoustic detector (4)and analyzes the signals without the noise, thereby obtaining theamplitude changing data and spectral data.

FIG. 2 is a sectional view of the catheter (2), wherein the endoscopicfibers (21), flush liquid passage hole (22), balloon dilation liquidpassage hole (23), laser light projecting fibers (24) and tip portioncontrol wire (25) are bundled and fixed in a transparent medium (26) andthe surface thereof is coated by a thin film. Moreover, the abovetransparent medium (26) also serves as an illumination light guide.

The endoscopic fiber (21) is made of materials having little dispersion,accomplishing the high accuracy of the both edge optical systemsparticularly in order to accomplish the high quality of the imageforming. Since in the present embodiment is used an excimer laser of apulse laser in the range of an ultraviolet rays in which a diseasedfocus can be removed with good efficiency and in safety, therefore thelaser light projecting fiber (24) is made of materials such as quartzwith good transmittance through which ultraviolet rays can betransmitted with high energy density and with low loss and the endsurface thereof is processed with high accuracy in order to suppress theheat generation at the end surface. The transparent medium (26) as theillumination light guide is made of visible light transmittablematerials with good flexibility such as multi-components group glass,plastic resin and rubber and the illumination light is projected fromthe tip section of the catheter (2). The tip of the catheter is guidedto the diseased part by the tip control wire which is controlled by acatheter controller (63) mentioned later in order that the edge portionof the catheter (2) is opposed to the diseased part.

The outer diameter of the catheter (2) accommodating the respectivecomponents (21) to (26) mentioned above is made extremely thinneddiameter of a few milli meters, preferably less than 1.5 mm. Therefore,it becomes possible to easily reach any part in the blood vessel by theguide of the catheter controller (63).

FIG. 3 is a diagram showing the details of the pulse laser oscillator(1), interface portion (6), controller (7) and image device (3)mentioned above. The pulse laser oscillator (1) comprises a laser outputcontrol unit (11) and laser oscillating unit (12), wherein the laseroutput control unit (11) controls the power of the laser light projectedfrom the laser oscillating unit (12). Since the laser oscillating unit(12) is composed of a pulse laser in a range of ultraviolet rays whichis absorbed largely by the tissue and has a large peak power, thediseased part can be removed with good efficiency and in safety.Therefore, the laser oscillating unit is composed of a pulse oscillationexcimer laser of noble gas halide such as XeCl, KrF and ArF. Moreover,(13) denotes a connecting portion for connecting the projected laserlight to the light leading fiber (24), which is composed of a minuteoptical system having little loss.

The interface portion (6) comprises; a Xe lamp (61) for applying visiblelight to said illumination light guide (26), a blood removing mechanism(62) for charging balloon dilation liquid (621) (such as isotonic sodiumchloride solution) and flush liquid (622) (liquid having little loss inthe range of the wave length of the used laser) into the balloondilation fluid passage hole (23) and flush liquid passage hole (22), anda catheter controller (63) having an operation mechanism for operatingthe control wire (25), which are respectively controlled by thecontroller (7). That is to say, the controller (7) drives the cathetercontroller (63) so as to reach the catheter (2) to a desired portion,thereby performing the ON/OFF control of the Xe lamp (61) and thecontrol of the blood removing mechanism (62).

The controller (7) also judges the sort of the diseased tissue and thedegree of the progress of the disease depending on the amplitudechanging data and spectrum data from the acoustic analyzer (5) andcalculates the optimum irradiation condition (amplitude, pulse width andpulse interval) in accordance with the degree of the progress of thedisease and transmits a control signal to the laser output control unit(11) depending on the optimum output data, thereby controlling theoutput level (10 mJ/pulse to 500 mJ/pulse), pulse width (2 nsec to 1μsec degree) and pulse repeating frequency (10 to 200 Hz degree) of thelaser output.

The image device (3) comprises a division optical system (31) dividingimage light generated from the endoscopic fibers (21), image receivingunit (32) receiving one of the divided light by CCD elements, spectrumanalyzing unit (33) obtaining the components of the fluorescent spectrumof the other divided light, image processing unit (34) compensating theoutput signals of the image receiving unit (32) and the spectrumanalyzing unit (33), monitor television (35) displaying the processedimage signal on the screen of the television, and VTR (36) for recordingthe image.

FIG. 4 is a schematic diagram showing an example of the above mentionedintracavitary laser operating device applied to a human body, whereinthe catheter (2) is inserted to a thrombus formed portion in a coronaryartery and the acoustic detector (4) is situated on the surface of thebody nearest to the thrombus portion. The laser light is projected tothe thrombus from the pulse laser oscillator (1) through the laserprojecting fibers (24) in the catheter (2). The acoustic detector (4)detects the acoustic wave which is generated from the diseased partbecause of the thermal expansion caused by the sudden heat absorption inthe neighborhood of the vaporization starting portion due to receivingthe laser irradiation by the diseased tissue. Subsequently, the acousticanalyzer (5) removes a noise such as a heart beat from the acousticwaves detected by the acoustic detector (4) and analyzes the signalwithout a noise, thereby obtaining the amplitude changing data andspectrum data. Subsequently, the controller calculates the optimumirradiation condition of the laser light to be irradiated to thediseased part depending on the data from the acoustic analyzer (5) so asto control the pulse laser oscillator mentioned above.

Next, the operating process of the above mentioned intracavitary laseroperating device is explained with reference to FIG. 5. First, as theprocess before operation, after the disinfection of the catheterinserting portion, anesthetization and supply of the catheter areperformed, the catheter controller (63) is driven through the drivecontroller (7) so that the catheter (2) is guided into a predeterminedblood vessel (such as a coronary artery). Subsequently, the balloondilation liquid (621) is charged into the balloon dilation fluid passagehole (23) so that the balloon (8) is expanded for stopping the bloodflow and the tip of the catheter (2) is fixed in the blood vessel by theballoon (8). Subsequently, the flush liquid (622) is immediately chargedinto the flush liquid passage hole (22) so that the blood in the lowerstream below the hemostasis portion is replaced to be made transparent.Upon observing by the monitor television (35), it is examined whether ornot there is a diseased part, and if there is no diseased part, theballoon (8) is constricted to recover the flow of the blood and thecatheter (2) is advanced to the other portion. If there is a diseasedpart, the pulse laser oscillator (1) is driven and the laser light isprojected to the diseased part. When the diseased part receives theprojection of the pulse laser light, the acoustic wave is generatedbecause of the thermal expansion caused by the sudden heat absorption atthe neighborhood of the vaporization starting portion. The generatedacoustic wave is detected by the acoustic detector (4) and analyzed bythe acoustic analyzer (5), thereby obtaining the amplitude changing dataof the acoustic wave and spectrum data. Subsequently, the controller (7)judges the sort of the diseased tissue and the degree of the progress ofthe disease depending on the amplitude changing data and the spectrumdata and calculates the optimum irradiation condition in accordance withthe sort of the diseased tissue and the progress degree of the disease,so that the laser light is projected to the diseased part undercontrolling the amplitude, pulse width and pulse intervals of the laserlight depending on the calculated data.

The processes as mentioned above are repeated until the diseased part iscompletely destroyed. If the diseased part is completely destroyed, theballoon (8) is constricted and the blood flow is recovered and then thecatheter (2) is pulled out. Subsequently, a necessary process afteroperation is performed and the operation is finished.

In addition, in this embodiment, though the acoustic detector isprovided outside the body, the acoustic detector can be attached to thetip of the catheter. In this case, the acoustic detector can be providedalso as a sensor for measuring blood pressure, and since it is possibleto detect the change of the blood pressure caused by the removal of thediseased part, not only the laser projection can be performed in safetybut also the effect of the treatment can be confirmed, that is stillmore effective. As an acoustic detector, there may be used asemiconductor pressure sensor, piezoelectric elements or optical fiberpressure sensor having a diaphragm provided on the tip of the opticalfiber. Moreover, though the explanation is made about the intravasculartreatment in this embodiment, it is also possible to apply the device tothe other treatments such as using the laser to destroy a calculus inurethra by using a similar device.

As described above, according to the present invention, since in thecase that, the catheter accommodating the endoscopic fibers and laserlight projecting fibers is inserted into the cavity and the diseasedpart in the cavity is searched by the endoscopic fibers so that thelaser light is projected to the diseased part through the laser lightprojecting fibers, it is possible to calculate the optimum irradiationcondition of the laser light to be projected to the diseased partdepending on the change of the acoustic wave from the diseased part soas to project the laser light to the diseased part based on said optimumirradiation condition, therefore, obtaining a specific effect ofavoiding a fear that a normal blood vessel wall is damaged or carbonizedor that a risk of a perforation in a blood vessel or a new re-stenosisis caused.

What is claimed is:
 1. An intracavitary laser operating device forprojecting laser light to a diseased part through laser light projectingfibers by inserting a catheter accommodating said laser light projectingfibers into a cavity, comprising:pulse laser oscillator means forgenerating laser light of a predetermined cycle; optic fiber means forreceiving said laser light and for supplying said light to said diseasedpart; acoustic receiver means for detecting an acoustic wave generatedfrom the diseased part; acoustic analyzer means, operatively coupled tosaid acoustic receiver means, for analyzing the acoustic wave detectedby said acoustic receiver means and for obtaining amplitude change dataand spectrum data of the acoustic wave; and controller means,operatively coupled to said acoustic analyzer means and to said pulselaser oscillator means, for calculating an optimum condition of thelaser light depending on said amplitude change data and said spectrumdata from said acoustic analyzer and for controlling said pulse laseroscillator device based on said optimum condition of the laser light;wherein said catheter has a tip portion, said tip portion having a side,said acoustic receiver is provided on the side of the tip portion, andsaid acoustic receiver means comprises measurement means for measuringblood pressure.